Hypersonic high enthalpy laminar flow over a 30◦ hollow cylinder flare is simulated using the GASP and GASPex software. The simulations are based on the experiments performed in the LENS-XX wind tunnel at the Calspan-University of Buffalo Research Center (CUBRC). The total enthalpy varies from 5.07 to 21.85 M J/kg. Simulations are performed using both the Park I and perfect gas models. Steady-state solutions obtained by Gauss-Seidel iteration and time-accurate integration are compared. Grid convergence of the simulations is shown. The heat transfer and pressure on the isothermal cold wall are compared with experimental data.